Slatted floors are used in a variety of equipment such as automated palletizing systems. When used in a palletizing system, the slatted floor defines a temporary surface onto which items that are being palletized are arranged. When the items are ready to be transferred onto another surface such as a pallet or a slip sheet, the slatted floor is moved horizontally from beneath the items so that the items are deposited onto an underlying surface.
A bi-parting slatted floor is defined by plural slats that define a unitary surface when the floor is in a closed position. When the floor is “opened”, the unitary surface splits along a mid-line and one section of the floor moves horizontally in a first direction and the other section of the floor moves horizontally in the opposite direction. The items collected on the slatted floor when it was closed are thus deposited onto the underlying surface when the bi-parting floor opens. In most instances, the underlying surface onto which the items are deposited is vertically movable so that the underlying surface is maintained in proximity to the lower surface of the slatted floor. Therefore, as the bi-parting floor opens the items that are being transferred to the underlying surface, for example, a pallet, are dropped as the slatted floor sections withdraw from beneath the items—it is desirable to minimize the distance that the items are dropped in order to minimize damage to the items and their contents.
Bi-parting slatted floors (and other slatted floors) are typically driven by chain drive systems that are driven by motors. Since in a bi-parting system the two portions of the floor that move necessarily move simultaneously in opposite directions, the chain system necessarily must move in opposite directions. This necessitates two sections of chain positioned adjacent the floor—typically beneath the slats. Previously, the two sections of chain have been vertically stacked relative to one another—that is, one chain is located vertically atop the other. Both chains are attached to the appropriate portions of the overlying slats with extension arms that extend from the chain links to the lower surface of the slats. The extension arms that are attached to the vertically lowermost section of chain and extend upwardly to the lower surface of the slats are necessarily relatively longer than the extension arms that are attached to the uppermost section of chain and extend upwardly to the lower surface of the slats; often there is a strong bending moment applied to the extension arms as the drive system starts up.
The vertically stacked sections of chain in prior chain drive systems for bi-parting slatted floors are therefore prone to a variety of problems, the first being damage caused to the chains and extension arms that interconnect the chains to the floor slats. When the drive motors start up, the bending moment on the extension arms can be very strong and this can result in the arms being bent. A second problem is that the vertically stacked sections of chain prevent the underlying surface—the pallet—from being moved into very close proximity to the bottom of the slatted floor. In other words, the upper surface of the pallet (or the upper surface of a layer of items already stacked on a pallet) can only be moved upwardly toward the lower surface of the slatted floor until the pallet's upper surface is adjacent the vertically stacked chains. Since the chains and associated hardware can be relatively heavy duty and robust, items accumulated on the slatted floor may have to “drop” several inches onto the pallet when the slatted floor is opened. This drop may cause damage to the items on the slatted floor, for example, boxes, or their contents.
There is a need therefore for a drive system for a bi-parting slatted floor that alleviates the problems caused by known stacked-chain systems, and to eliminate the damage caused by dropping items from the slatted floor onto the underlying surface.
The present invention comprises a chain drive system for a bi-parting slatted floor in which the vertically stacked drive chains of the prior art systems are replaced by a drive system that relies upon two continuous loops of chain, one on each side of the slatted floor that move in opposite directions beneath the slats. Operative sections of a single chain between driven and idler shafts are arranged side-by-side in the same horizontal plane, at the same level. A single drive motor drives both loops of chain. The side-by-side orientation of the operable portions of the chain eliminates the long extension arms necessary to attach the chain links to the lower surface of the slats, and allows for substantial improved vertical movement of the underlying surface. In other words, with the operative portions of the chain sections arranged side-by-side in the same horizontal plane, the vertical amount of space occupied by the chains is significantly decreased compared to the vertically stacked chains of the prior art. This allows the underlying surface onto which items are deposited to be moved vertically upward next to the lower surface of the slats to a significantly greater extent. The additional vertical movement of the underlying surface provides for substantial operational benefits and eliminates the significant vertical drop distance associated with vertically stacked chain systems.